What metal has a mass of 21.535g?

The metal with a mass of 21.535 grams is likely to be a specific quantity of cobalt, which has an Atomic Mass of approximately 58.933 g/mol. However, the mass you've provided is not a standard measurement for any known metal; it may refer to a specific sample size or quantity rather than an intrinsic property of a metal. To identify the metal accurately, additional context or information about its volume or state would be needed.